The present invention relates to friction clutch assemblies for motor vehicles and particularly to a continuously rotating anti-friction release bearing adapted to be attached to the friction clutch.
In general, friction clutches are provided with a spring release member which is in the form of a diaphragm or cup-shaped spring washer having a plurality of radially inwardly directed arms defining a central bore. Such spring release mechanisms are generally dish-shaped somewhat like a belleville washer or spring. The clutch release bearing itself is adapted to engage the face of the spring release member so as to be continuously self-centering and to be attached to the spring release member so as to be operable thereon. A well known construction is shown in U.S. Pat. No. 2,485,214, wherein the anti-friction release bearing is housed in a special type housing and the inner ring is extended axially therefrom. The inner ring of the bearing projects into the bore of a diaphragm type spring release member and is provided with an annular groove on its surface which engage the tongues or ends of the arms of the spring release member. This construction is very complicated due to the composite design of the housing and of the massively constructed anti-friction bearing required.
In another well known form of friction clutch, described in German patent publication DAS No. 1,555,408, the anti-friction release bearing is arranged in the plane of the belleville spring washer through its inner diameter. The outer race ring is joined securely with the arms of the belleville spring washer. This construction is likewise very complicated because the anti-friction bearing must be in the form of a massive solid heavy bearing and is mounted on a guide sleeve. The guide sleeve is itself adjustably and movably mounted on a shoulder attached to the gear housing. Furthermore, because of the arrangement of the release bearing in the plane of the belleville spring a large bore is necessary in the spring. As a result the lever arm for the release force is necessarily smaller and thus great release forces are necessary to operate the clutch. Still further, since the bearing is centered over the guide sleeve mounted on the shoulder, an unnecessarily large axial offset between the guide sleeve and the bore of the belleville spring is created. Thus additional reactive forces are exerted by the bearing on the spring and vice versa. It is thus not possible to obtain a truly self-centering bearing relative to the rotating parts of the clutch.
It has been furthermore well known to provide a clutch release bearing in which the race rings are made of thin sheet metal rather than being made of massive solid rings. In these embodiments, however, it has not been possible to provide a unitary assembly ready for installation in which the clutch and the clutch release bearing are furnished pre-assembled.
It is the object of the present invention to provide a friction clutch and release bearing assembly which overcomes disadvantages and defects of the prior art.
It is a further object of the present invention to provide a clutch release bearing and assembly in which the several parts are simple to manufacture and which can be assembled without great outlay in time or cost with the clutch to form a unitary assembly. In addition it is an object of the present invention to provide a clutch release bearing of the type described which may be easily dismantled and replaced and repaired.
It is a further object of the present invention to provide a clutch release bearing adapted for attachment to a friction clutch in which the bearing is easily centered with regard to the clutch release spring and which is further self-centering under operable load conditions.
These objects, other objects and numerous advantages will be apparent from the following disclosure of the preferred form of the present invention.